This is an idea that has been bouncing around for a while, but is now apparently seen in experiments: real-world photosynthesis taking advantage of quantum mechanics. (Story in Wired, via @symmetrymag. Here’s the Nature paper on which it’s all based.)
The idea is both simple and awesome: you want to transport energy through an “antenna protein” in a plant cell to the “reaction-center proteins” where it is chemically converted into something useful for the rest of the plant. Obviously you’d like to transport that energy in the most efficient way possible, but you’re in a warm and wet environment where losses are to be expected. But the plants somehow manage the nearly impossible, of sending the energy with nearly perfect efficiency through the judicious use of quantum mechanics.
We can think about this in terms of Feynman’s way of talking about quantum mechanics: rather than a particle taking a unique path between two points, as in classical mechanics, a quantum particle takes every possible path, with simple paths getting a bit more weight than complicated ones. In the case of the protein, different paths for the energy might be more or less efficient at any particular moment, but this bit of quantum trickery allows the energy to find the best possible route at any one time. Imagine at rush hour, if your car could take every possible route from your home to the office, and the time it officially took would be whatever turned out to be the shortest path. How awesome would that be?
The reason you can’t do that is that your car is a giant macroscopic object that can’t really be in two places at once, even though the world is governed by quantum mechanics at a deep level. And the reason for that is decoherence — even if you tried to put your car into a superposition of “take the freeway” and “take the local roads,” it is constantly interacting with the outside world, which “collapses the wave function” and keeps your car looking extremely classical.
Proteins in plants aren’t as big as cars, but they’re still made of a very large number of atoms, and they’re constantly bumping into other molecules around them. That’s why it’s amazing that they can actually maintain quantum coherence long enough to pull off this energy-transport trick. Previous studies had hinted at the possibility, but only by cooling the proteins down and shielding them from external jiggling. This new work happens at room temperature in the context of marine algae, so it seems to indicate that it can happen in real environments.
One step closer to building my teleportation machine. Get to work, quantum engineers!
So is the shortest path via spacetime curved or linear?..at micro_quantum levels it seems that the Quantum has an efficiency value that constrains the “all probable paths” into the most economic, and thus efficient paths of curveture?
The shortest path through macro spacetime is via curveture, the longest route is straight, it may be that at quantum levels the, straight_laser_path may be causing local loop_holes to appear in spacetime itself?..this may be the added energy that shows up in the data
If Nature really has such an efficient process at molecular level, then why did plants evolve into systems that do NOT actually produce the said effect?..I mean they would only need to convert the photons once, and once only?
I don’t think this changes the picture much for the (im)possibility of quantum effects in neural functioning. The timescale for the decoherence in the photosynthesis paper is listed to be >300 femtoseconds = 3 x 10^-13 s. If you look at Tegmark’s paper on neural functioning, you’ll see that he estimated that the decoherence time in the brain could be on the order of 10^-13 s, which is compatible with this. But the dynamical time scale for neural activity is milliseconds, which is 10^10 times longer. There’s a big difference between moving an electron around one molecule vs. activity of an entire neuron. See here for details:
http://space.mit.edu/home/tegmark/brain.html
Fascinating. Thank you for the post.
I was wondering what you think of the modeling ?
http://condensedconcepts.blogspot.com/2010/02/nature-publishes-17-parameter-fit-to-20.html
So does this make the idea of quantum processes as a crucial part of the functioning of neurons any more plausible?”
I was going to ask the same question. Anyone want to chance an answer?
Sean, what do you think of a) Penrose’s ideas on quantum consciousness? b) Penrose’s ideas on initial entropy of the universe, c) Penrose’s idea that gravity is responsible for the collapse of the wave function (this last one is just a blog-level simplification of what he actually claims).
While quantum coherence is probably still unlikely when it comes to larger systems like neuronal assemblies, I think this shows its very possible that that non-trivial quantum effects are involved throughout biology. This is very exciting and hopefully there’s much more to come. Being too skeptical about the possiblities will only slow down the science.
There’s a certain similarity between this mechanism and the evolution of networks in communication.
It’s simply not efficient to establish unique circuits between A and B in any large system.
So packet switched networks evolved.
This required:-
* Breaking down messages into identifiable packets (quanta of information)
* The ability to re-sequence packets at the destination address. (maintain coherence)
* A system of nodes with the ability to store and forward packets (a pathway)
* A system for interrogating the state of the network and routing packets. (maximise use of pathway)
Such a system evolves quite logically from the initial requirement to make the most efficient use of the network. (principle of least action)
So it’s not hard to see how evolution could have come up with such a result for the chemical pathways used for photosynthesis.
As far as I am aware, photons are the thingos that carry electrical attraction/replusion. So the reason I see that building outside is because some electron in the sun has an electrical interaction with a dye molecule in my retina, and the net effect of the atmosphere, the reflectance of the building’s surface, and the shape of my eyeball is that it’s most likely that it’s dye molecule in such a position as to be part of forming an image.
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